Reliability-improving structure of reciprocating compressor

ABSTRACT

In a reliability-improving structure of a reciprocating compressor, by minimizing vibration noise occurred in operation, adjusting a quantity of compression gas accurately, measuring an air gap in order to uniform an air gap of a reciprocating motor in an assembly process and firming combination between an inner stator combined with a piston for compressing gas so as to perform a linear reciprocating motion with the piston and a magnet fixedly combined with the inner stator, reliability of a reciprocating compressor can be improved.

TECHNICAL FIELD

[0001] The present invention relates to a reciprocating compressor, andin particular to a reliability-improving structure of a reciprocatingcompressor capable of minimizing vibration noise occurred in operation,adjusting a quantity of compression gas accurately, measuring an air gapin order to uniform an air gap of a reciprocating motor of thereciprocating compressor and firming combination between an inner statorwhich is combined with a piston for compressing gas and performs alinear reciprocating motion with the piston and a magnet fixedlycombined with the inner stator.

BACKGROUND ART

[0002] In general, a reciprocating compressor is for compressing fluidsuch as air or coolant gas, etc. A compressor includes a motor partinstalled in a sealed container and generating a driving force and acompression unit for sucking and compressing coolant gas by receivingthe driving force of the motor.

[0003] The compressor is divided into a rotary compressor, areciprocating compressor and a scroll compressor, etc. according to agas compression mechanism of the motor part and compression part.

[0004] As depicted in FIG. 1, in the rotary compressor, according torotation of a rotor 2 of a motor part M installed in a sealed container1, a rotational shaft 3 inserted into the rotor 2 is rotated. By therotation of the rotational shaft 3, a rolling piston 5 inserted into aneccentric portion 3 a of the rotational shaft 3 and arranged in acompression space P of a cylinder 4 contacts to the inner circumferenceof the compression space P of the cylinder 4. In that contact state,with a vane (not shown) inserted into a certain side of the cylinder 4in order to divide a high pressure region and a low pressure region, therolling piston 5 compresses the coolant gas sucked into a suction hole 4a of the cylinder 4 and discharges the gas through a discharge flow pathwhile being rotated in the compression space P of the cylinder 4, andthe operation is performed repeatedly.

[0005] As depicted in FIG. 2, in the reciprocating compressor, a crankshaft 13 inserted into a rotor 12 is rotated according to rotation ofthe rotor 12 of a motor part M installed in a sealed container 11. Bythe rotation of the crank shaft 13, a piston 14 combined with aneccentric portion 13 a of the crank shaft 13 compresses coolant gassucked through a valve assembly 16 combined with the cylinder 15 anddischarges the gas through the valve assembly 16 while performing alinear reciprocating motion inside a compression space P of a cylinder15, and the operation is performed repeatedly.

[0006] And, as depicted in FIG. 3, in the scroll compressor, arotational shaft 23 having an eccentric portion 23 a inserted into arotor 22 is rotated according to rotation of the rotor 22 of a motorpart M installed in a sealed container 21. According to the rotation ofthe rotational shaft 23, because a slewing scroll 24 connected to theeccentric portion 23 a of the rotational shaft 23 performs a slewingmotion while being engaged with a fixed scroll 25, volume of pluralcompression pockets formed by involute-curved wraps 24 a, 25 arespectively formed at the slewing scroll 24 and the fixed scroll 25 isdecreased, and accordingly coolant gas is sucked, is compressed and isdischarged in the operation. The operation is performed repeatedly.

[0007] Hereinafter, the rotary compressor, the reciprocating compressorand the scroll compressor operated by different compression mechanismswill be described in the structure and reliability aspects.

[0008] First, in the structure aspect of the rotary compressor, therotary compressor includes the rotational shaft 3 having the eccentricportion 3 a, the rolling piston 5 inserted into the eccentric portion 3a and plural balance weights combined with the rotor 2 so as to maintainthe rotation balance of the eccentric portion 3 a. Because the rotarycompressor has lots of construction parts, a structure thereof is alittle complicate.

[0009] In addition, in the reliability aspect of the rotary compressor,because the eccentric portion 3 a formed at the rotational shaft 3 andthe rolling piston 5 are rotated eccentrically, lots of vibration noiseoccurs in rotation.

[0010] And, in the structure aspect of the reciprocating compressor, thereciprocating compressor includes the crank shaft 13 having theeccentric portion 13 a, the piston 14 combined with the crank shaft 13and a balance weight 13 b for maintaining the rotation balance of theeccentric portion 13 a. Because the reciprocating compressor has lots ofconstruction parts, a structure thereof is a little complicate.

[0011] In addition, in the reliability aspect of the reciprocatingcompressor, because the eccentric portion 13 a formed at the crank shaft13 is rotated eccentrically, vibration noise occurs, in addition, thevalve assembly 16 is operated in suction and discharge, lots ofsuction/discharge noise occurs.

[0012] And, in the structure aspect of the scroll compressor, the scrollcompressor includes the rotational shaft 23 having the eccentric portion23 a, the slewing scroll 24 and the fixed scroll 25 having theinvolute-curved wraps and a balance weight for maintaining the rotationbalance of the eccentric portion 23 a. Because it has lots ofconstruction parts, a structure thereof is very complicate. In addition,it is very difficult to fabricate the slewing scroll 24 and the fixedscroll 25.

[0013] In addition, in the reliability aspect of the rotary scroll,vibration noise occurs in the slewing motion of the slewing scroll 24and the eccentric motion of the eccentric portion 23 a formed at therotational shaft 23.

[0014] As described above, in the rotary compressor, the reciprocatingcompressor and the scroll compressor, the compression part compressesgas by receiving the rotational force of the motor part, when acompressor is installed in a cooling cycle, the number of rotations ofthe motor part has to be reduced or the rotation of the motor part hasto be stopped in order to adjust a quantity of compression gas, andaccordingly it is difficult to adjust a quantity of the compression gasaccurately.

[0015] In addition, by respectively forming the eccentric portion 3 a,13 a, 23 a at the rotational shaft rotated by receiving the rotationalforce of the motor part, the balance weight 6, 13 b, 26 are required,lots of driving force is consumed, vibration noise occurs in theoperation, and accordingly reliability of the compressor is lowered. Inaddition, because of complicated structure, assembly productivity islowered.

TECHNICAL GIST OF THE PESENT INVENTION

[0016] In order to solve the above-described problems, it is an objectof the present invention to provide a reciprocating compressor which iscapable of minimizing vibration noise in operation, adjusting a quantityof compression gas accurately and improving a compression performance.

[0017] In addition, it is another object of the present invention toprovide a reciprocating compressor which is capable of simplifyingassembly of construction parts and minimizing assembly error.

[0018] It is yet another object of the present invention to provide areciprocating compressor which is capable of measuring an air gap of areciprocating motor in order to uniform an air gap of the reciprocatingmotor in an assembly process.

[0019] And, it is still another object of the present invention toprovide a reciprocating compressor which is capable of constructing areciprocating motor generating a linear reciprocating driving force; andcombining firmly an inner stator combined with a piston so as to performa linear reciprocating motion along the piston with a magnet fixed tothe inner stator.

[0020] In order to achieve the above-mentioned objects, areliability-improving structure of a reciprocating compressor inaccordance with the present invention includes a container having asuction pipe in which gas is sucked; an outer stator disposed in thecontainer, and an inner stator inserted into the outer stator so as tobe movable; a reciprocating motor having a magnet fixedly combined withthe inner stator so as to place between the inner stator and the outerstator; a front frame having a cylinder unit at which a through hole isformed and combined so as to support the outer stator of thereciprocating motor; a piston inserted into the through hole of thecylinder unit of the front frame, combined with the inner stator of thereciprocating motor, receiving a linear reciprocating driving force ofthe reciprocating motor and performing a linear reciprocating motionwith the inner stator and the magnet; a rear frame unit for covering thepiston and fixedly supporting the reciprocating motor; a resonancespring unit for supporting movement of the piston, the inner stator andthe magnet elastically; and a valve unit for sucking and discharging gasaccording to the linear reciprocating motion of the piston.

BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are included to provide afurther understanding of the invention and are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and together with the description serve to explain theprinciples of the invention.

[0022] In the drawings:

[0023]FIG. 1 is a sectional view illustrating the conventional rotarycompressor;

[0024]FIG. 2 is a sectional view illustrating the conventionalreciprocating compressor;

[0025]FIG. 3 is a sectional view illustrating the conventional scrollcompressor;

[0026]FIG. 4 is a sectional view illustrating an embodiment of areliability-improving structure of a reciprocating compressor inaccordance with the present invention;

[0027]FIG. 5 is an enlarged-sectional view illustrating a motor part ofthe compressor in FIG. 4;

[0028]FIG. 6 is a sectional view illustrating a modified combination ofa piston and an inner stator of the reciprocating compressor inaccordance with the embodiment of the present invention;

[0029]FIG. 7 is a sectional view illustrating another embodiment of areliability-improving structure of a reciprocating compressor inaccordance with the present invention;

[0030]FIG. 8 is an exploded-sectional view illustrating anotherembodiment of the reliability-improving structure of the reciprocatingcompressor in accordance with the present invention;

[0031]FIG. 9 is a sectional view illustrating yet another embodiment ofa reliability-improving structure of a reciprocating compressor inaccordance with the present invention;

[0032]FIG. 10 is a sectional view illustrating a different example ofyet another embodiment of the reliability-improving structure of thereciprocating compressor in accordance with the present invention;

[0033]FIG. 11 is a sectional view illustrating a different example ofyet another embodiment of the reliability-improving structure of thereciprocating compressor in accordance with the present invention;

[0034]FIG. 12 is a sectional view illustrating a different example ofyet another embodiment of the reliability-improving structure of thereciprocating compressor in accordance with the present invention;

[0035]FIG. 13 is a sectional view illustrating a different example ofyet another embodiment of the reliability-improving structure of thereciprocating compressor in accordance with the present invention;

[0036]FIG. 14 is a sectional view illustrating a different example ofyet another embodiment of the reliability-improving structure of thereciprocating compressor in accordance with the present invention;

[0037]FIG. 15 is a sectional view illustrating a different example ofyet another embodiment of the reliability-improving structure of thereciprocating compressor in accordance with the present invention;

[0038]FIG. 16 is a sectional view illustrating a different example ofyet another embodiment of the reliability-improving structure of thereciprocating compressor in accordance with the present invention; and

[0039]FIG. 17 is a sectional view illustrating an operation state of areciprocating compressor having a reliability-improving structure inaccordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0040] Hereinafter, the preferred embodiments of a reliability-improvingstructure of a reciprocating compressor in accordance with the presentinvention will be described in detail with reference to accompanyingdrawings.

[0041] First, FIG. 4 is a sectional view illustrating an embodiment of areliability-improving structure of a reciprocating compressor inaccordance with the present invention. As depicted in FIG. 4, in thereciprocating compressor, a suction pipe in which gas is sucked iscombined with a certain side of a container 100, and the bottom surfaceof the container 100 is filled with oil.

[0042] And, a front frame 200 having a certain shape is arranged in thecontainer 100, a reciprocating motor 300 for generating a linearreciprocating driving force is fixedly combined with the front frame200, and a certain-shaped rear frame unit 500 is combined with the otherside of the reciprocating motor 300 so as to support it.

[0043] In the front frame 200, a plate portion 230 having a certain areais extended-formed from a side of a cylinder unit 220 having a throughhole 210, and a support portion 240 is curved-extended from the plateportion 230.

[0044] A reciprocating motor 300 includes an outer stator 310 consistingof a cylindrical laminated body and a wound coil 340 combined with thelaminated body; a cylindrical inner stator 320 inserted into the outerstator 310 in the length direction so as to perform a linearreciprocating motion; and a magnet 330 fixedly combined with the innerstator 320 so as to place between the outer stator 310 and the innerstator 320.

[0045] In more detail, the inner stator 320 and the magnet 330 arefixedly combined with each other as one body. As depicted in FIG. 5, alength of the inner stator 320 is longer than that of the outer stator140. In other words, the both ends of the inner stator 320 are extendedmore than the both ends of the outer stator 310. Because of that, asmooth flux path is secured between the inner stator 320 at which themagnet 330 is fixedly combined and the outer stator 310, and accordinglyoperation reliability of the reciprocating compressor can be improved.

[0046] In the reciprocating motor 300, the outer stator 310 is fixedlycombined with the support portion 240 of the front frame 200.

[0047] And, the certain-shaped piston 400 is inserted into the throughhole 210 of the cylinder unit 220 of the front frame 200 and is combinedwith the inner stator 320 of the reciprocating motor 300.

[0048] The cylindrical-shaped piston 400 includes a piston body portion410 having an inner gas flow path F and a ring-shaped flange portion 420curved-extended from the end of the piston body portion 410. The pistonbody portion 410 is inserted into the cylinder unit through hole 210 ofthe front frame 200, and the flange portion 420 is fixedly combined withthe inner stator 320.

[0049] A compression space P is formed by the cylinder unit through hole210 of the front frame 200 and the piston 400.

[0050] The rear frame unit 500 has a cap shape and is fixedly combinedwith the outer stator 310 of the reciprocating motor 300 so as to coverthe piston 400, the inner stator 320 and the magnet 330.

[0051] And, a resonance spring unit 600 is included in order to supportthe movement of the piston 400, the inner stator 320 and the magnet 330elastically.

[0052] The resonance spring unit 600 includes a certain-shaped firstspring supporter 610 fixedly combined with the inner stator 320 and thepiston 400 so as to place at the front frame side; a second springsupporter 620 fixedly combined with the other side of the inner stator320 so as to place at the rear frame unit side; a first spring 630placed between the first spring supporter 610 and the front frame 200;and a second spring 640 placed between the second spring supporter 610and the rear frame unit 500.

[0053] It is preferable to form the first and second springs 610, 620 ascoil springs.

[0054] And, a valve unit 700 is included in order to suck and dischargegas according to the linear reciprocating motion of the piston 400.

[0055] The valve unit 700 includes a suction valve 710 fixedly combinedwith the end of the piston 400 and opening/closing the gas flow path Fof the piston 400; a discharge cover 720 for covering the cylinder unitthrough hole 210 of the front frame 200; a discharge valve 730 placedinside the discharge cover 720 and opening/closing the through hole 210of the front frame 200; and a valve spring 740 placed inside thedischarge cover 720 and elastically supporting the discharge valve 730.

[0056] A discharge pipe 20 for discharging gas is combined with a sideof the discharge valve 730.

[0057] And, an oil supply means 800 is arranged at the lower portion ofthe front frame 200, the sucked oil is supplied to each portion at whichfriction occurs by the oil supply means 800.

[0058] In the meantime, in a modified combination of a piston and aninner stator of the reciprocating compressor in accordance with theembodiment of the present invention shown in FIG. 6, the piston 400includes a piston body portion 410 having a certain length and arrangedin the compression space P; a flange portion 420 curved-formed at theend of the piston body portion 410 so as to have a certain area; and afixed guide portion 430 extended-formed at a surface of the flangeportion 420 so as to have a certain outer diameter and a length in theaxial direction.

[0059] And, the inner stator 320 includes a cylindrical body 321; afirst combining portion 322 formed inside the cylindrical body 321 so asto have an inner diameter corresponded to the outer diameter of theflange portion 422 of the piston 400; and a second combining portion 323abutting on he first combining portion 322 and pierced-formed throughthe cylindrical body 321 so as to have an inner diameter corresponded tothe outer diameter of the fixed guide portion 430 of the piston 400.

[0060] And, the first combining portion 322 of the inner stator 320 isfixedly inserted into the flange portion 420 of the piston 400, and thesecond combining portion 323 is fixedly combined with the fixed guideportion 430 of the piston 400.

[0061] And, a side of the first spring supporter 610 and a side of thesecond spring supporter 620 are inserted into the first combiningportion 32 of the inner stator 320.

[0062] In the meantime, as depicted in FIG. 4, in the construction ofthe reciprocating motor for generating the linear reciprocating drivingforce, an air gap G is one of factors determining efficiency of themotor.

[0063] In more detail, when the air gap G is big, efficiency of themotor is lowered due to flux loss, when the air gap G is small,efficiency of the motor is improved. However, when the air gap G issmall, an assembly process is intricate, and damage of constructionparts may occur because contact between other construction parts.

[0064] In more detail, with the above-mentioned structure of thereciprocating compressor, when the air gap G of the reciprocating motoris minimized and whole construction parts are assembled in that state,due to fabrication error and assembly error of the construction parts,the air gap G of the reciprocating motor can not be maintaineduniformly, interference between the construction parts may occur, andaccordingly reliability of the reciprocating compressor may be lowered.

[0065] Accordingly, a remedy for the above-mentioned problem will bepresented.

[0066]FIG. 7 is a sectional view illustrating another embodiment of areliability-improving structure of a reciprocating compressor inaccordance with the present invention. As depicted in FIG. 7, in thereciprocating compressor, a suction pipe 10 in which gas is sucked iscombined with a side of a certain-shaped container 100.

[0067] And, a front frame 200 having a certain shape is installed in thecontainer 100, a reciprocating motor 300 for generating a linearreciprocating driving force is fixedly combined with the front frame200, and a certain-shaped rear frame unit 500 is combined with the otherside of the reciprocating motor 300 so as to support it.

[0068] In the front frame 200, a plate portion 230 having a certain areais extended-formed from a side of a cylinder unit 220 having a throughhole 210, a support portion 240 is curved-extended from the plateportion 230, and plural measuring holes 250 are pierced through theplate portion 240. The plural measuring holes 250 formed at the plateportion 240 are placed on the same circle.

[0069] A compression space P is formed by the through hole 210 of thecylinder unit 220 of the front frame 200 and the piston 400.

[0070] A reciprocating motor 300 includes an outer stator 310 consistingof a cylindrical laminated body and a wound coil 340 combined with thelaminated body; a cylindrical inner stator 320 inserted into the outerstator 310 in the length direction so as to perform a linearreciprocating motion; and a magnet 330 fixedly combined with the innerstator 320 so as to place between the outer stator 310 and the innerstator 320.

[0071] The outer stator 310 is a laminated body 312 in whichcertain-shaped plural thin plates are laminated, it has an inner throughhole 311, and the wound coil 340 is combined with an opening groove 313formed at the inner circumference of the through hole 311.

[0072] The inner stator 320 is a laminated body in which plural thinplates are laminated radially as a cylindrical shape, and the magnet 330is fixedly combined with the outer circumference of the inner stator 320so as to place between the outer stator 310 and the inner stator 320.

[0073] An interval between the outer surface of the magnet 330 and theinner circumference of the outer stator 310 is called the air gap G.

[0074] A length of the inner stator 320 is longer than that of the outerstator 140, and the outer stator 310 is fixedly combined with thesupport portion 240 of the front frame 200.

[0075] The rear frame unit 500 has a cap shape and is fixedly combinedwith the outer stator 310 of the reciprocating motor 300 so as to coverthe piston 400, the inner stator 320 and the magnet 330.

[0076] And, a resonance spring unit 600 is included in order to supportthe movement of the piston 400, the inner stator 320 and the magnet 330elastically.

[0077] The resonance spring unit 600 includes a certain-shaped firstspring supporter 610 fixedly combined with the inner stator 320 and thepiston 400 so as to place at the front frame side; a second springsupporter 62—fixedly combined with the other side of the inner stator320 so as to place at the rear frame unit side; a first spring 630placed between the first spring supporter 610 and the front frame 200;and a second spring 640 placed between the second spring supporter 610and the rear frame unit 500.

[0078] And, a valve unit 700 is included in order to suck and dischargegas according to the linear reciprocating motion of the piston 400.

[0079] The valve unit 700 includes a suction valve 710 fixedly combinedwith the end of the piston 400 and opening/closing the gas flow path Fof the piston 400; and a discharge cover 720 for covering the cylinderunit through hole 210 of the front frame 200 is fixedly combined withthe front frame 200 by plural fastening bolts 750.

[0080] The discharge cover 720 includes a cover portion 721 having a capshape and an extended portion 722 curved-extended from the end of thecover portion 721. In the discharge cover 720, when the cover portion721 covers the through hole 210 of the front frame 200 and the extendedportion 722 contacts with the plate portion 230 of the front frame 200,the plural fastening bolts 750 are pierced-fastened through the extendedportion 722, and accordingly the discharge cover 720 is fixedly combinedwith the front frame 200.

[0081] Herein, the extended portion 722 of the discharge cover 720closes the measuring hole 250 formed at the plate portion 230 of thefront frame 200, and it is preferable a side of the first spring 630 isarranged in the measuring hole 250 of the plate portion 230 of the frontframe 200 and is supported by the extended portion 722 of the dischargecover 720.

[0082] And, a discharge valve 730 for opening/closing the through hole210 and a valve spring 740 for elastically supporting the dischargevalve 730 are inserted into the cover portion 721 of the discharge cover720.

[0083] In the meantime, fixing of the inner stator 310 constructing thereciprocating motor 300 and performing the reciprocating motion togetherwith the piston 400 by being connected to it and the magnet 330 fixedlycombined with the inner stator 310 will be described in detail.

[0084] First, the inner stator 320 has the cylindrical shape so as to beinserted into the outer stator 310 with a certain interval, the magnet330 is formed so as to have a certain thickness and area, and the magnet330 is adhered to the outer circumference of the inner stator 320 by anadhesive agent.

[0085] However, in the above-described structure, because the magnet 330is adhered to the outer circumference of the inner stator 320 by theadhesive agent, when the inner stator 320 and the magnet 330 perform thelinear reciprocating motion together with the piston 400 in the axialdirection by being elastically supported by the spring unit 600, themagnet 300 may be separated from the inner stator 320 and cause damagedue to operation vibration or a long term operation, and accordinglyreliability of the reciprocating compressor may be lowered.

[0086] Hereinafter, a remedy for the problem will be presented.

[0087]FIG. 9 is a sectional view illustrating yet another embodiment ofa reliability-improving structure of a reciprocating compressor inaccordance with the present invention. As depicted in FIG. 9, thereciprocating compressor includes a container 100 having a suction pipe10; a front frame 200 having a cylinder unit 220 at which a through hole210 is formed and arranged inside the container 100; a reciprocatingmotor 300 in which an inner stator 350 is inserted so as to be movableinside an outer stator 310 fixedly combined with a side of the frontframe 200 in the axial direction and a magnet 360 is combined with theinner stator 350 so as to be placed between the inner stator 350 and theouter stator 310; a piston 400 inserted into the through hole 210 of thecylinder unit 200 of the front frame 200, combined with the inner stator350 of the reciprocating motor 300 and performing a linear reciprocatingmotion with the inner stator 350 and the magnet 360 by receiving alinear reciprocating driving force of the reciprocating motor 300; arear frame unit 500 for converting the piston 400 and fixedly supportingthe outer stator 310 of the reciprocating motor 300; a resonance springunit 600 for elastically supporting the movement of the piston 400, theinner stator 310 and the magnet 360; and a valve unit 700 for suckingand discharging gas according to the linear reciprocating motion of thepiston 400.

[0088] The outer stator 310 of the reciprocating motor 300 includes acylindrical body 311 having a certain length and a through hole 310formed inside the cylindrical body 311, an opening groove 313 having acertain width and depth is formed at the inner circumference of thethrough hole 312 of the cylindrical body 311, and a wound coil 340 iscombined with the opening groove 313.

[0089] The inner stator 350 consists of a cylindrical body 351 having alength longer than that of the outer stator 310, is inserted into thethrough hole 312 of the outer stator 310 with a certain interval, andthe piston 400 is combined with the cylindrical body 351.

[0090] In more detail, a certain interval is maintained between theinner circumference of the cylindrical body 311 of the outer stator 310and the outer circumference of the cylindrical body 351 of the innerstator 350.

[0091] And, the magnet 360 is fixedly combined with the inner stator 350so as to place between the outer stator 310 and the inner stator 350.

[0092] The magnet 360 consists of plural magnets, and they are arrangedon the outer circumference of the inner stator 350 in thecircumferential direction at regular intervals.

[0093] In fixing of the magnet 360 to the inner stator 350, aninstallation groove 352 having a certain depth is formed at the outercircumference of the cylindrical body 351 of the inner stator 350, andthe magnet 360 is fixedly inserted into the installation groove 352 ofthe inner stator 350.

[0094] The magnet is formed so as to have a certain thickness and area.In more detail, the magnet 360 is formed as a curved plate having aradius curvature corresponded to a radius of curvature of the outercircumference of the inner stator 350. The installation groove 352 ofthe inner stator 350 has a shape and a depth corresponded to the shapeand depth of the magnet 360. The magnet 360 can be fixedly inserted intothe installation groove 352 or adhered to the installation groove 352 byan adhesive agent.

[0095] And, as depicted in FIG. 10, when the magnet 360 is inserted intothe installation groove 352, the magnet 360 can be fixed to the innerstator 350 by hardening carbon fiber C onto part of the outercircumference of the inner stator 350 including the magnet 360.

[0096] And, in a modified example of the installation groove 352, theinstallation groove 352 is formed as a circular band shape onto theouter circumference of the inner stator 350 in the circumferentialdirection so as to have a length and a depth corresponded to the magnet360, and the magnet 360 is fixedly inserted into the installation groove352 at regular intervals.

[0097] In a different example of yet another embodiment of thereliability-improving structure of the reciprocating compressor inaccordance with the present invention shown in FIG. 11, the installationgroove 352 in which the magnet 360 is fixedly inserted is formed at theouter circumference of the cylindrical body 351, and a protrusion 353 isrespectively formed on the outer circumference of the cylindrical body351 so as to have a length and an interval corresponded to the magnet360.

[0098] The protrusion 353 is projected-extended from the outercircumference of the cylindrical body 351 of the inner stator 350 so asto have a certain thickness and a height.

[0099] The magnet 360 is formed as a curved plate having a radiuscurvature corresponded to a radius of curvature of the outercircumference of the inner stator 350 and is fixedly inserted into theinstallation groove 352 formed by the protrusions 353.

[0100] In a different example of yet another embodiment of thereliability-improving structure of the reciprocating compressor inaccordance with the present invention shown in FIG. 12, the magnet 360is contacted to the outer circumference of the inner stator 350 so as toplace between the outer stator 310 and the inner stator 350, and acertain-shaped magnet fixing member 370 is fixedly combined with theinner stator 350 and fixes the magnet 360.

[0101] The magnet 360 has a certain thickness and area, and it is formedas a curved plate having a radius curvature corresponded to a radius ofcurvature of the outer circumference of the inner stator 350.

[0102] And, the magnet fixing member 370 includes a horizontal contactportion 371 contacted and joined to the outer circumference of the innerstator 350; and a vertical portion 372 curved-extended from thehorizontal contact portion 371 so as to be shorter than a height of themagnet 360 and supporting the side surface of the magnet 360. The magnetfixing member 370 is respectively combined with the both sides of themagnet 360 in the length direction in order to support the magnet 360.

[0103] The magnet fixing member 370 having a length corresponded to alength of the magnet 360 in the long axis direction is fixedly combinedwith the both sides of each magnet 360, or the magnet fixing member 370is formed as a circular shape in order to fix-combine collectively themagnets 360 arranged on the outer circumference of the inner stator 350in the circumferential direction.

[0104] In a different example of yet another embodiment of thereliability-improving structure of the reciprocating compressor inaccordance with the present invention shown in FIG. 13, the magnet 360is contacted to the outer circumference of the inner stator 350 so as toplace between the outer stator 310 and the inner stator, and acertain-shaped magnet fixing member 370 is fixedly combiend with theinner stator 350 and fixes the magnet 360.

[0105] The magnet 360 has a certain thickness and area, and it is formedas a curved plate having a radius curvature corresponded to a radius ofcurvature of the outer circumference of the inner stator 350.

[0106] And, the magnet fixing member 370 includes a horizontal contactportion 371 contacted and joined to the outer circumference of the innerstator 350; a vertical portion 372 curved-extended from the horizontalcontact portion 371 so as to be shorter than a height of the magnet 360and supporting the side surface of the magnet 360; and a horizontalfixing portion 373 curved-extended from the vertical portion 372 andsupporting the top surface of the magnet 360. The magnet fixing member370 is respectively combined with the both sides of the magnet 360 inthe length direction in order to support the magnet 360.

[0107] The magnet fixing member 370 having a length corresponded to alength of the magnet 360 in the long axis direction is fixedly combinedwith the both sides of each magnet 360, or the magnet fixing member 370is formed as a circular shape in order to fix-combine collectively themagnets 360 arranged on the outer circumference of the inner stator 350in the circumferential direction.

[0108] In a different example of yet another embodiment of thereliability-improving structure of the reciprocating compressor inaccordance with the present invention shown in FIG. 14, a stepped groove361 corresponded to a thickness of the horizontal fixing portion 373 ofthe magnet fixing member 370 is formed on the top surface of the magnet360 arranged so as to contact with the outer circumference of the innerstator 350, the horizontal fixing portion 37 is respectively insertedinto the stepped groove 361 of the magnet 360, and accordingly themagnet 360 is fixedly combined.

[0109] Herein, the top surface of the magnet 360 and the top surface ofthe horizontal fixing portion 373 are the same surface.

[0110] In a different example of yet another embodiment of thereliability-improving structure of the reciprocating compressor inaccordance with the present invention shown in FIG. 15, the lengthdirection both sides of the magnet 360 contacted to the outercircumference of the inner stator 350 are formed so as to be slant.

[0111] And, the magnet fixing member 370 includes a horizontal contactportion 371 contacted and joined to the outer circumference of the innerstator 350; and a slant fixing portion 374 slant-extended from thehorizontal contact portion 371 so as to have an angle corresponded tothat of a side slant surface 362 of the magnet 360 in order to supportthe slant surface 362 of the magnet 360.

[0112] The magnet fixing member 379 is respectively combined with theouter circumference of the inner stator 350 so as to place on the bothsides of the magnet 360 in the long axis direction in order to fix themagnet 360.

[0113] It is preferable to join the magnet fixing member 370 onto theouter circumference of the inner stator 350 by welding.

[0114] In a different example of yet another embodiment of thereliability-improving structure of the reciprocating compressor inaccordance with the present invention shown in FIG. 16, plural magnets360 are arranged on the outer circumference of the inner stator 351 inthe circumferential direction.

[0115] And, a magnet fixing member 370 for covering not only the magnets360 but also part of the outer circumference of the inner stator 350 isformed in order to fix the magnets 360.

[0116] The magnet fixing member 370 is carbon fiber C. After coveringpart of the outer circumference of the inner stator 250 including themagnets 360 with the carbon fiber C, the carbon fiber C is hardened.

[0117] In the meantime, it is preferable to make the outer stator 310and the inner stator 350 as laminated bodies by laminating plural thinplates radially in order to make them have a cylindrical shape.

[0118] Hereinafter, the operation and advantages of thereliability-improving structure of the reciprocating compressor inaccordance with the present invention will be described.

[0119] First, when power is applied to the reciprocating compressor,current flows around the wound coil 340 of the reciprocating moor 300,flux is formed between the outer stator 310 and the inner stator 320,and the inner stator 320 and the magnets 330, 360 generate a linearreciprocating driving force by mutual operation between the flux of theouter stator 310 and the inner stator 320 and flux of the magnets 330,360.

[0120] As depicted in FIG. 17, the linear reciprocating driving force ofthe inner stator 320 and the magnets 330, 360 is transmitted to thepiston 400, the piston 400 performs the linear reciprocating motion inthe cylinder unit through hole 210 of the front frame 200 with the innerstator 320 and the magnets 330, 360. According to the linearreciprocating motion of the piston 400, coolant sucked into the suctionpipe 10 with the operation of the valve unit 700 flows through the gasflow path F of the piston 400, is sucked into the compression space P,is compressed, and the compressed high temperature-high pressure isdischarged through the discharge cover 720 and the discharge pipe 20.The operation is performed repeatedly.

[0121] In the meantime, in the linear reciprocating motion of the piston400 with the inner stator 320 and the magnets 330, 360 of thereciprocating motor 300, the resonance spring unit 600 stores-emits thelinear reciprocating driving force of the reciprocating motor 300 aselastic energy and induces a resonance motion.

[0122] In more detail, when the piston 400 is moved to a bottom deadcenter, the first spring 630 is tensed, simultaneously the second spring640 is compressed. When the piston 400 is moved to a top dead center,the first spring 630 is compressed, simultaneously the second spring 640is tensed and elastically supports the piston 400, the inner stator 320and the magnets 330, 360.

[0123] In the present invention, because the piston 400 receives thelinear reciprocating driving force of the reciprocating motor 300 andcompresses gas while performing the linear reciprocating motion in thethrough hole 210 of the front frame 200, the operation is performed in astable state.

[0124] In more detail, unlike the conventional art, not adapting amechanism for compressing gas with volume variation using a rotationmotion or a mechanism for compressing gas by converting a rotationmotion into a linear reciprocating motion, but adapting a mechanism fortransmitting the linear reciprocating driving force to the piston 400and compressing gas while performing the linear reciprocating motion inthe through hole 210 of the front frame 200, the gas compressingoperation is stable, vibration can be minimized, and there is no need toadd an additional part in order to stabilize the operation.

[0125] In addition, when it is possible to control a linear operationaldistance of the reciprocating motor 300, a stroke, namely, anoperational distance of the piston 400 can be adjusted, and accordinglyit is possible to adjust a quantity of compression gas accurately.

[0126] In the present invention, because the inner stator 320, themagnets 330, 360 are combined with the piston 400 and are movedtogether, it is possible to minimize an air gap G between the outerstator 310 and the inner stator 320 of the reciprocating motor 300 andfacilitate air gap management.

[0127] In the present invention, a structure and the number ofconstruction parts of a motor part for generating a linear reciprocatingdriving force and a compression part for compressing gas can besimplified.

[0128] And, as depicted in FIG. 8, by inserting a gap gauge K throughthe measuring hole 250 of the front frame 200, an air gap G between theouter stator 310 and the inner stator 320 of the reciprocating motor 300can be measured. Afterward, the first spring 630 is inserted through themeasuring hole 250.

[0129] Herein, the other side of the first spring 630 is supported bythe first spring supporter 610.

[0130] And, the discharge cover 720 of the valve unit 700 is combinedwith the front frame 200 so as to cover the through hole 210 and themeasuring hole 250 of the front frame 200, and the discharge cover 720is fixedly combined with the front frame 200 by the plural bolts 750.

[0131] Herein, the other side of the first spring 630 is supported bythe extended portion 722 of the discharge cover 720.

[0132] In the present invention, the magnet 360 combined with the innerstator 350 is fixedly inserted into the installation groove 352 formedon the outer circumference of the cylindrical body 351 of the innerstator 350, the combining is firm, particularly it is possible tomaintain the firm combining state of the magnet 360 even in the axialdirection or circumferential direction vibration.

[0133] In addition, because the magnet 360 is inserted-fixed to theinstallation groove 352 of the inner stator 350, an air gap between theinner stator 350 and the outer stator 310 is reduced, and accordinglyoutput of the motor can be improved.

[0134] And, when the magnet 360 is fixedly combined with the innerstator 350 by the magnet fixing member 370, because the magnet 360 issupported-fixed to the inner stator 350 by the magnet fixing member 370,it is possible to firm the combining of the magnet, particularly it ispossible to maintain the firm combining state of the magnet 360 even inthe axial direction or circumferential direction vibration.

INDUSTRIAL APPLICABILITY

[0135] As described above, in a reliability-improving structure of areciprocating compressor in accordance with the present invention,because an operation state is stable, vibration and noise can beminimized, and accordingly reliability of the reciprocating compressorcan be improved. Because it is possible to simplify construction parts,fabrication and assembly processes can be performed easily, andaccordingly assembly productivity can be improved. In addition, byreducing an air gap of a reciprocating motor for generating a linearreciprocating driving force, output of the reciprocating motor can beimproved. And, it is possible to adjust accurately a quantity ofcompression gas discharge by a piston stroke control, unnecessary losscan be reduced, and accordingly power consumption can be lowered.

[0136] In addition, in the present invention, in the assembly process,by measuring an air gap of the reciprocating motor in order to maintainthe air gap uniformly, it is possible to reduce fabrication error andassembly error by preventing irregular air gap occurrence in theassembly, damage due to wrong operation can be prevented, a stableoperation can be performed, and accordingly reliability of thereciprocating compressor can be improved.

[0137] In addition, in the present invention, by combining firmly aninner stator and magnets of the reciprocating motor, when the pistonreceives the linear reciprocating driving force of the reciprocatingmotor and compresses gas while performing the linear reciprocatingmotion together with the inner stator and the magnet of thereciprocating motor, it is possible to prevent separation of the magnetsfrom the inner stator even in vibration occurrence or long termoperation, and accordingly reliability of the reciprocating compressorcan be improved.

1. A reliability-improving structure of a reciprocating compressor,comprising: a container having a suction pipe in which gas is sucked; anouter stator disposed in the container, and an inner stator insertedinto the outer stator so as to be movable; a reciprocating motor havinga magnet fixedly combined with the inner stator so as to place betweenthe inner stator and the outer stator; a front frame having a cylinderunit at which a through hole is formed and combined so as to support theouter stator of the reciprocating motor; a piston inserted into thethrough hole of the cylinder unit of the front frame, combined with theinner stator of the reciprocating motor, receiving a linearreciprocating driving force of the reciprocating motor and performing alinear reciprocating motion with the inner stator and the magnet; a rearframe unit for covering the piston and fixedly supporting thereciprocating motor; a resonance spring unit for supporting movement ofthe piston, the inner stator and the magnet elastically; and a valveunit for sucking and discharging gas according to the linearreciprocating motion of the piston.
 2. The structure of claim 1, whereinthe resonance spring unit includes: a certain-shaped first springsupporter fixedly combined with a side of the inner stator or the pistonso as to place at the front frame side; a second spring supporterfixedly combined with the other side of the inner stator or the pistonso as to place at the rear frame unit side; a first spring arrangedbetween the first spring supporter and the front frame; and a secondspring arranged between the second spring supporter and the rear frameunit.
 3. The structure of claim 1, wherein a length of the inner statorof the reciprocating motor is longer than that of the outer stator andis arranged in a movement direction of the reciprocating motor.
 4. Thestructure of claim 1, wherein the piston includes; a piston body portionhaving a certain length and arranged in the compression space P; aflange portion curved-extended from the end of the piston body portionso as to have a certain area; and a fixed guide portion extended-formedat a surface of the flange portion so as to have a certain outerdiameter and a length in a length direction; wherein the inner statorincludes: a cylindrical body; a first combining portion formed insidethe cylindrical body so as to have an inner diameter corresponded to anouter diameter of the flange portion of the piston; and a secondcombining portion abutting on the first combining portion andpierced-formed through the cylindrical body so as to have an innerdiameter corresponded to an outer diameter of the fixed guide portion ofthe piston; herein the first combining portion of the inner stator isfixedly inserted into the flange portion of the piston, and the secondcombining portion of the inner stator is combined with the fixed guideportion of the piston.
 5. The structure of claim 1, wherein acertain-shaped plural measuring holes are pierced through the frontframe after assembling construction parts of the reciprocatingcompressor in order to insert a gap gauge for measuring an air gap ofthe reciprocating motor into an air gap of the reciprocating motorthrough the front frame, and an opening/closing means foropening/closing the measuring holes is arranged on the front frame. 6.The structure of claim 5, wherein the opening/closing means is includedin the valve unit, and the opening/closing means consists of an extendedportion arranged on a discharge cover for covering a compression spacein order to cover the measuring holes; and plural fastening bolts forcombining the discharge cover with the front frame.
 7. The structure ofclaim 5, wherein a side of the first spring is arranged on the measuringhole of a plate portion of the front frame and is supported by anextended portion of the discharge cover.
 8. The structure of claim 1,wherein an installation groove having a certain depth is formed at theouter circumference of the inner stator which is inserted into the outerstator of the reciprocating motor generating the linear reciprocatingdriving force so as to perform the linear motion, and a magnet having acertain thickness and area is fixedly inserted into the installationgroove of the inner stator so as to place between the outer stator andthe inner stator.
 9. The structure of claim 8, wherein the installationgroove of the inner stator is formed by protrusions projected from theouter circumference of the inner stator so as to have a certain height.10. The structure of claim 8, wherein the magnet is fixed by coveringpart of the outer circumference of the inner stator including the magnetwith carbon fiber and hardening the carbon fiber.
 11. The structure ofclaim 1, wherein the inner stator is inserted into the outer stator ofthe reciprocating motor for generating the linear reciprocating drivingforce so as to perform the linear motion, the magnet is contacted to theouter circumference of the inner stator so as to place between the innerstator and the outer stator, and a certain-shaped magnet fixing memberis fixedly combined with the inner stator and fixedly supports themagnet.
 12. The structure of claim 11, wherein the magnet fixing memberis respectively arranged on the both sides of the magnet in the longaxis direction and includes: a horizontal contact portion having acertain thickness and length, contacted and joined to the outercircumference of the inner stator; and a vertical portioncurved-extended from the horizontal contact portion so as to have aheight shorter than that of the magnet and supporting the side surfaceof the magnet.
 13. The structure of claim 11, wherein the magnet fixingmember is respectively arranged on the both sides of the magnet in thelong axis direction and includes: a horizontal contact portion having acertain thickness and length, contacted and joined to the outercircumference of the inner stator; and a horizontal fixing portioncurved-extended from the horizontal contact portion so as to have aheight corresponded to that of the magnet and supporting the top surfaceof the magnet.
 14. The structure of claim 13, wherein a stepped groovecorresponded to a thickness of the horizontal fixing portion is formedon the top surface of the magnet arranged so as to contact to the outercircumference of the inner stator, and the horizontal fixing portion isrespectively arranged on the stepped groove of the magnet.
 15. Thestructure of claim 11, wherein the length direction-both sides of themagnet contacted to the outer circumference of the inner stator areslant, and the magnet fixing member includes: a horizontal contactportion having a certain thickness and length, contacted and joined tothe outer circumference of the inner stator; and a slant fixing portionslant-extended from the horizontal contact portion so as to have anangle corresponded to that of a slant side surface of the magnet inorder to support the slant surface of the magnet.
 16. The structure ofclaim 11, wherein the magnet is fixed by covering part of the outercircumference of the inner stator including the magnet with carbon fiberand hardening the carbon fiber.